ME-SFI safety fuel shutoff, function - GF07.61-P-3018G

ENGINE 273 in MODEL 463.202/222/236/237 up to 31.5.12 as of model year 2009/YoM 08

Fig 1: Identifying ME-SFI Safety Fuel Shutoff Function Chart

Courtesy of MERCEDES-BENZ USA

Function requirements for safety fuel shutoff for the ME gasoline injection and ignition system (motor electronics) (ME), general points

Circuit 87M ON (engine control ON)
Engine running

ME-SFI safety fuel shutoff, general points

To ensure traffic and passenger safety, safety fuel shutoff is applied.

The ME-SFI [ME] control unit manages the safety fuel shutoff according to the following sensors and signals:

Crankshaft Hall sensor, engine speed
Throttle valve actuator, throttle valve position
Restraint systems control unit, direct crash signal

ME-SFI safety fuel shutoff, function sequence

The safety fuel shutoff is activated by the ME-SFI [ME] control unit under the following conditions:

Mechanical fault in throttle valve actuator function sequence
Function sequence for engine speed signal missing
Crash signal function sequence

Mechanical fault in throttle valve actuator function sequence

When evaluating the throttle valve position, if the ME-SFI [ME] control unit detects a mechanical fault in the throttle valve actuator, engine speed is limited to about n = 1400 rpm at idle and about n = 1800 rpm in driving mode by shutting off the fuel injection valves (Y62).

The engine speed is detected by the ME-SFI [ME] control unit based on the signal from the crankshaft Hall sensor.

Function sequence for engine speed signal missing

If the engine speed signal generated by the ME-SFI [ME] control unit fails, the fuel pump is shut off via the ME-SFI [ME] control unit.

Crash signal function sequence

If the ME-SFI [ME] control unit receives a crash signal directly from the restraint system control unit it switches the fuel pump off and actuates the fuel injection valves for a short time to depressurize the fuel system.

Component description for ME-SFI [ME] control unit	N3/10	GF07.61-P-6000G
Component description for rear SAM control unit with fuse and relay module	N10/2	GF54.21-P-6030G
Component description for supplemental restraint system control unit	N2/7	GF91.60-P-4068G